text: A type of pneumatic motor, known as a rotary vane motor, uses air to produce rotational motion to a shaft.  The rotating element is a slotted rotor which is mounted on a drive shaft. Each slot of the rotor is fitted with a freely sliding rectangular vane. The vanes are extended to the housing walls using springs, cam action, or air pressure, depending on the motor design. Air is pumped through the motor input which pushes on the vanes creating the rotational motion of the central shaft.  Rotation speeds can vary between 100 and 25,000 rpm depending on several factors which include the amount of air pressure at the motor inlet and the diameter of the housing.
  One application for vane-type air motors is to start large industrial diesel or natural gas engines.  Stored energy in the form of compressed air, nitrogen or natural gas enters the sealed motor chamber and exerts pressure against the vanes of a rotor.  This causes the rotor to turn at high speed.  Because the engine flywheel requires a great deal of torque to start the engine, reduction gears are used.  Reduction gears create high torque levels with the lower amounts of energy input.  These reduction gears allow for sufficient torque to be generated by the engine flywheel while it is engaged by the pinion gear of the air motor or air starter.